Modified Active Constellation Extension for PAPR Reduction of Space-Frequency Block Coded OFDM Systems

Abstract

In this paper, the Active Constellation Extension (ACE) technique is applied to Space Frequency Block Coded (SFBC) OFDM systems to reduce the Peak to Average Power Ratio (PAPR). For the extension of this technique to SFBC systems, it will be shown that the space frequency coded signals are the combination of several subframes and that the ACE method may be applied to these subframes. Using this model, an iterative ACE method, based on Projection Onto Convex Sets (POCS), is introduced. At each iteration, the time domain samples of the subframes are clipped based on their e ect on the samples of all antennas. Then, the clipped subframes are ltered and the signals of the antennas are constructed from the modi ed subframes. The simulation results show that the performance of the proposed method is very close to the performance of the ACE method in the single antenna OFDM system.